According to a 2014 review of cancer medicines from the World Health Organisation, EOC is the most common type of ovarian cancer and has a five-year survival rate of about 40 per cent, researchers said.

It has a relatively low lifetime risk that is less than one per cent, but that can increase up to 40 per cent if there is a family history of the disease.

A majority of patients (80 per cent) experience a relapse after their initial treatment with chemotherapy; therefore, a more effective line of treatment is needed.

The group’s in vitro experiments showed that EOCs, which usually proliferate in the presence of pro-tumour M2 macrophages, showed inhibited growth after introduction of ONA.

This was thought to be due to ONA influence on STAT3, a transcription factor known to be involved in both M2 polarisation and cancer cell proliferation.

The team also found that ONA inhibited the pro-tumour functions of myeloid-derived suppressor cells (MDSC), which are associated with the suppression of the anti-tumour immune response of host lymphocytes, by using preclinical sarcoma model.

ONA was also found to enhance the effects of anti-cancer drugs by strengthening their anti-proliferation capabilities.

This was considered to be a result of ONA’s suppression of M2 polarised macrophages, researchers said.

The study shows that ONA reduces the progression of malignant ovarian cancer tumours by interfering with the pro-tumour function of myeloid cells.

ONA appears to activate anti-tumour immune responses by nullifying the immunosuppressive function of myeloid cells. It has the potential to enhance existing anti-cancer drugs while also having little to no cytotoxic effects on normal cells, researchers said.

No side effects in animals have been observed. With a little more testing, an oral ONA supplement could greatly benefit cancer patients, they said.